Histioteuthis is a genus of squid and the only member of the Histioteuthidae family. It goes by the common namecock-eyed squid, because in all species the right eye is normal-sized, round, blue and sunken; whereas the left eye is at least twice the diameter of the right eye, tubular, yellow-green, faces upward, and bulges out of the head.

^Chun, Carl (1975). The Cephalopoda. Israel Program for Scientific Translations. p. 120. ISBN978-0-7065-1259-5. Histioteuthis is characterized by such a large membrane ("sail") [...] This "sail" is a strong, muscular cutaneous membrane which surrounds the 1st, 2nd and 3rd arms